Approaches for state-level sector attribution models in relation to national-level models #371
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I expect one difference here is the number of unique activity sets present in the GHG model that each have separate attribution approaches. In the linked approach for GHG_state_m2, number 2 above, each activity set from the national FBS is replicated from the original method and then further attributed to states. Some sectors in the national method will receive emissions from multiple activity sets (e.g., stationary combustion from natural gas, stationary combustion from coal, non-energy use of fossil fuels). If we started with the final FBS already aggregated we would lose much of that distinction. Or at least that was my thinking as I approached this. The employment FBS doesn't face this issue since it has just a single attribution approach. |
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I agree with @bl-young that both approaches should yield the same result. For state Employment, I used the national Employment FBS to save time. For the state water FBS, I will not use the national water FBS because the method for state/national for most of the activity sets is the same (uses state level data), but the national model is aggregated to national level at the end - there is no reason to attribute the national FBS to states as that adds unnecessary step. |
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The State GHG method is all set, currently labeled as _m3.
Comparisons at the sector level are equivalent, with just a few exceptions. One source of those exceptions is that the StateGHGI data is slightly more precise. So in a few cases where direct attribution is used, I've pulled the data directly from StateGHGI, instead of pulling it from GHG_national and attributing to states (which would be a less direct approach). E.g., here: flowsa/flowsa/methods/flowbysectormethods/GHG_state_2019_m3.yaml Lines 10 to 55 in 81d439c Are we ok with this, or would we rather ALL data come from the national FBS? |
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Another note on locations for the state models. There should be 52 location. 50 states, DC, and an Overseas region, to have parity with the StateIO model locations. We can also use the Overseas region for balancing as needed. @catherinebirney we will need a FIPS code for this region. |
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Here is the first attempt at a summary level national model (m2). The differences here are a few activities that can be directly attributed, and the use of Summary Make/Use of the target year instead of 2012 Detail. Activities that no longer need to be attributed:
Note: Emissions to agricultural sectors are mapped to 111 and 112, both of which aggregate to 111CA at the Summary level. However, for the FBS we leave them at 3-digit NAICS, so I use equal attribution instead of a USDA CoA dataset to split them to those sectors (which eliminates the need for that attribution source entirely). This may have consequences when we move from the summary model to the detail model at the national level. (and/or see #371 (reply in thread)) Currently I am not attributing EIA_MECS any further (i.e., using equal attribution), but will need to review that decision. (i.e., does MECS require further disaggregation for 3 or 4-digit NAICS, I wouldn't think too often) Commit: 824f992 I will be comparing this model (m2) to the detail model (m1) aggregated to summary sectors. |
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Here is a summary to detail model issue that's worth exploring:
For the Summary to Detail attribution, we need to extend 2211 to 6 digits. In this case, we would simply use equal attribution because, which is currently what we do in the detail model (as we don't differentiate by fuel type):
Unfortunately FlowBySector() does not have an equally_attribute function: |
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I wanted to summarize where things stand. We have three versions of the national method:
I believe m3 is the intended goal for the national model, and like m3, we expect to use m2 as the base for the state models. |
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An updated review of the state model (m2) which is built from the national model at the summary level (m2). The comparison of flow totals is below, and the sector/flow comparison is attached. This is for 2020 which aligns with https://github.com/USEPA/USEEIOStateMethod/pull/39.
All sector/flow totals that are not equal (< 0.05%):
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We discussed for select sectors, where the State Inventory GHGI data is not as refined as the national inventory, and therefore using it as an attribution source can obscure differences within sectors, that we could instead find an alternate economic based allocation source. One example is CO2 aviation emissions, which are primarily assigned directly to 481 from Table 3.13. StateGHGI does not differentiate CO2 emissions from various non-road transportation sources, so we get a very wide range of coefficients (see figure). Instead we can use something like the following which proportionally attributes the national emissions for any given sector based on each states use of petroleum in that sector:
It turns out though, that due to calculations in stateio, that this leads to identical coefficients for this sector for all states (I've been looking at 481 specifically). I assume this is because the stateio use tables keep a consistent use share for each state (i.e., 324 use is 7% of total sector output in every state, therefore we are essentially distributing these emissions across states proportional to output -> therefore they have the same coefficients).
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Regarding the CAP_HAP method, if we stick with the same approach as is done for GHGs, we would need a national summary model, which is then used to build a state summary model and a national detail model. Under this approach, the national summary model, like GHGs, would use the summary make/use tables of the appropriate years, but in some cases revert back to using the 2012 detail make/use where needed. To generate the state model from the national model, we would then use the state level emissions dataset to further attribute national emissions to each state. However in this case, the state level emissions dataset is the same as the primary emissions dataset (since NEI data are available by state/county). This would manifest as something like the following, which is just a repeat of what is done in the national model (where its gets aggregated).
I would propose in this case, despite that it deviates from the approach for GHGs, that we start with a state level model as the core model, and use that to build the national summary and national detail. (This would essentially be the current state CAP_HAP) |
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Summary of plan for CAP_HAP methods: A state level NAICS-6 model will form the core model for all CAP_HAP methods.
CAP_HAP_state_m1: Is a summary model that combines and aggregates these data to summary level, and adds StEWI |
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As of cf8bd94, we can now create a summary use table disaggregated to detail in flowsa based on the new IO tables. @WesIngwersen thoughts on how we want to name these FBS? |
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@bl-young Did the existing |
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Models with state-level resolution might be created independently from national-level models when flow sources differ
e.g.
https://github.com/USEPA/flowsa/blob/2db51cfd74c11bfedb894000350826f47e9763d3/flowsa/methods/flowbysectormethods/GHG_state_common.yaml
but at the risk that state totals (+ residual) do not sum to national totals for one or more sectors.
Another alternative is to intentional use the same flow sources for national and state level models but there can be multiple approaches to this.
Use a national-level FBS as the only flow source. e.g.,
https://github.com/USEPA/flowsa/blob/319a73acc56a30fad9cf748be920c7785f58563f/flowsa/methods/flowbysectormethods/Employment_state_2012.yaml
Use the same FBAs as flow sources for both national and state-level models. e.g.,
https://github.com/USEPA/flowsa/blob/319a73acc56a30fad9cf748be920c7785f58563f/flowsa/methods/flowbysectormethods/GHG_state_2019_m2.yaml
This discussion is for sharing insights and reasoning into the latter two approaches.
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